It is known to provide inserts to interconnect wall constructing blocks together to construct vertical or inclined earth retaining walls. An example of such system can be found in my U.S. Pat. No. 5,528,873 issued on Jun. 25, 1996. The use of pins to interconnect blocks together in crib work which form earth retaining wall is also described in U.S. Pat. No. 2,092,385 issued on Sep. 7, 1997. However these pins provide for positive interconnection and do not permit angulation or displacement of the earth retaining block one on top of the other to form either curved walls or inclined walls or straight walls. The use of pins to interlock construction blocks is also described in U.S. Pat. No. 1,704,941 issued on Jun. 10, 1926. However, such interconnection technique cannot achieve the construction of curved walls due to the fact that the inserts are very long and maintain the blocks in fixed position. Also, because some of these blocks are provided with grooves both on the top and on the bottom surfaces thereof, the structural strength of the block is diminished, and often the blocks will become damaged when they are tumbled to give the blocks a stone-like appearance to imitate real stones. It is customary when constructing curved retaining walls that the stones be interlocked with one another.
Another disadvantage of wall construction block of the type referred in my above-referenced U.S. patent, is that the blocks need to be laid at precise positions with respect to one another and tilted at their ends whereby to position an insert partly under the block and partly projecting out of the end wall of the block in order to interconnect blocks in side-by-side relationship as well as in vertical relationship. It is also necessary to clean the grooves of any debris, such as sand, prior to the insertion of the inserts to provide proper fitting. This is particularly so when walls are being repaired and earth debris has infiltrated into the grooves with time.